1) Field of the Invention
The present invention relates to massage devices, and particularly to a driven structure which moves continuously and reciprocally and is utilized at the back section of a massage chairs or in the interior of a pillow.
2) Description of the Prior Art
Since conventional massage devices installed on chairs or the interior sections of pillows for massaging back of a user must be capable of massaging the entire surface area of the back, they must move reciprocally and vertically to the back of the user. The reciprocating moving device of such conventional massage driving structures includes a single direction rotational rod, belt, chain, or other related means as well as a motor-based forward and backward rotation massage structure capable of performing a straight reciprocal motion.
However, since the prior art device needs a complicated drive structure that impels a pair of shafts to rotate, this will increase production cost and installation space. Therefore, there are manufacturing and utilization complexity and thus the prior art is not practical.
Another individually driven single rotary-direction device has a rotary shaft impelled by a direct current motor or an alternating current motor in which each of the two extremities of the reciprocating driven shaft must be equipped with an actuating control device which enable the rotational direction of the motor to be reversed each time the shaft contacts the distal ends, thereby, switching the driven shaft to rotate clockwise or counter-clockwise and to carry the massage device to move forward and then reverse the move direction backward to other end of travel. Although such a method compromises the production cost and space occupied, each time the moving directions of the driven shaft is switched during operation, it is impossible to avoid to generate transient current which will be applied to the motor so as to induce a fluctuating current, resulting in short random noises indicating high torque loads that shorten the lifetime of the motor. In situations of frequent utilization, since the back section of the massage device moves continuously and reciprocally, such condition causes the motors of such devices to malfunction or burn out and then require to be repaired or updated by a new one.
The primary objective of the present invention is to provide a reciprocally moving apparatus, wherein a single long driven shaft between two shaft blocks on a base plate is installed. The middle section of the driven shaft includes a clockwise helical trench and a counter-clockwise helical trench which are arranged on the surface of the driven shaft and cross over one another alternatively so as to be formed as a rod with two crossed helical trenches. A recess is formed in an upper side of a central area of the massage device for installing an active link block. A mounting lock cover covers on the recess and a cotter hole is formed in a top center section of the mounting lock cover for being inserted by an axial pin at a top end of the active link block, enabling to hold the active link block within the recess. Moreover. A guide plate with two tips at two upper edges is extended from a lower end of the active link block. The guide plate is inserted into one of the clockwise helical trench and the counter-clockwise helical trench.
Another objective of the present invention is to provide a reciprocally moving apparatus, wherein due to a single driven shaft and a rotational driving operation, reciprocal movement of a massage device can be achieved without any actuating control device to be installed at two distal ends of the driven shaft for controlling reversal of the positive and negative polarities without needing to control the electrical current of a driving motor. Therefore, in addition to have a simplified device and circuitry, since there is no positive and negative polarity alternation, a large electrical current will not be generated.
Another object of the present invention is to provide a reciprocally moving apparatus, wherein a single direction driving mode is performed. In this mode, the transmission relationship of the gears between the motor and the driven shaft is suspended. An upper and an lower sections of respective teeth sections of the gears each engaged to the front end motor shaft of the motor are transferred via driven gear at a distal end of the driven shaft and an engager which is a single direction clutch. After a user selects to input a current with a reverse polarity, the motor drives the shaft in the reverse direction such that the driven shaft forms a driving-separation relationship. In this moment, the massage device is not carried and moved, it stops at the original position for the fixed-point massage operation.